The ad hoc mode of radio networks is traditionally based on two distinct approaches. The first, called “flat approach,” consists of considering that all nodes are of equal importance at all times and requires a significant signal exchange between the nodes, part of the bandwidth therefore being dedicated to that purpose. Furthermore, it is difficult to synchronize the network globally, to optimize the use of radio resources without a network coordinator (TDMA protocol difficult to establish in a “flat” network) and the load of the network becomes significant in case of link losses.
The second approach consists of structuring an ad hoc network as a stack of clusters, each cluster for example being a cell of the Point-to-MultiPoint (PMP) type as in WiMAX (IEEE 802.16). The resulting network is typically based on a tree structure as shown in FIG. 1. The central node, called Network Head (NH), at the top of the structure, i.e. which is not attached to any higher-level station, is responsible for coordinating the network. The nodes are connected at most to a single station of a higher hierarchical level. In document FR 0801869, published as FR 2 929 781, hereby incorporated by reference herein, a node of such a network comprises two radios per node, each radio in turn being able to be base station (BS) for a lower-order cluster or subscriber station (SS) for the higher-order cluster. This approach already makes it possible to substantially limit modifications to be made to the MAC (Medium Access Control) layer, and combines efficiency and cost reduction.
WO 2009/150245, hereby incorporated by reference herein, purportedly discloses sub channel generation for a wireless mesh network. A method, apparatus and computer program divide an available bandwidth into a plurality of frequency bands or channels, divide each of the plurality of frequency bands or channels into a plurality of orthogonal sub-carriers, organize the sub-carriers into a plurality of sub-channels, and assign at least some of the generated sub-channels to at least one corresponding radio link between parent and child nodes of a mesh network.
U.S. Publication No. 2002/0077151, hereby incorporated by reference herein, purportedly discloses a nanoCell base station for providing radio connectivity among one or more mobile stations, one or more base transceiver stations or one or more other nanoCell base stations.